Operating Manual and Scavenging Primer with
Receiving Information, Installation and Maintenance
you for your order. I believe you will
find this Veterinary Vacuum/Scavenging Interface by far, more reliable, easier
to install and simpler to use than any other such device on the market.
Features of this HEMC interface:
- Two scavenging tube
inlet ports (1) that accept either 19 mm or 22 mm tubing. Optionally the interface can be supplied
with three or four inlet ports.
- An integral scavenging
backup system in the form of a charcoal canister (2) that scavenges the
anesthetics, other than N2O, from the waste gas in the event of suction
system disconnect or failure. This "back up" mode also facilitates
transport to other areas of the hospital or can be used where vacuum is
- There are no inlet,
outlet or overpressure relief valves to foul, fail or need servicing.
- The scavenging flow
rate can be precisely set (3) between 1 and 10 liters per minute and is
easily verifiable at any time at a glance from most any angle.
- It is configurable such
that it will plug into a wall outlet, hang from a ceiling drop, or pole
mount on most any size round pole.
- Durable life lasting
chrome plated solid brass construction with stainless steel hardware
provides MRI compatible as
packing slip you received with this interface lists the part number for this
interface (000A3463) along with the additional parts needed to customize its
gas connections and mounting options to your needs as discussed when you placed
your order. You have received only ONE part completely assembled that is made up of
all that is listed on the packing slip, you received TWO parts only if the hose
assembly was required to be separate.
Wall mount and ceiling drop mount units:
Your interface should be supplied with the type of quick
Chemetron, Schrader or Puritan style) or DISS
fitting you requested at the time your order was taken. The ceiling drop interfaces will have an
additional 90° elbow fitting at the top of the flowmeter facilitating the
vertical connection to the drop.
plug the interface into either the wall outlet or the ceiling drop.
- Connect one 19mm or
22mm tube from each device you wish to scavenge onto the inlet ports (1)
on the top of the interface. If
an inlet port is not to be used it MUST BE occluded, a red cap plug is included for this
- Be sure the appropriate
size reservoir bag is securely attached to the bottom 22 mm connector (4)
to the left of the flowmeter. A
2-liter "evacuation purple", the color standard, bag is included and is
appropriate for most applications.
One liter and one-half liter bags are also available as is an
adapter for a 2", 30-liter bag.
- Weigh the charcoal
canister. Mark the weight in grams
on its label along with the date of installation.
the canister to the 15 mm port (2) on the bottom side and to the right of
WARNING: This vacuum/scavenging interface WILL NOT
work properly without the charcoal canister, even if the vacuum system is
Pole mount units:
- Your interface should
have been shipped with a pole mount plate and clamps to accommodate the
size pole you told us you would be mounting the interface on. Place the interface in the desired
position on the pole and close the two clamps AS TIGHTLY AS POSSIBLE.
- Follow steps 1 through
- Pole mount interfaces
may either have an attached hose or may have a separate hose that needs to
be connected to the back of the interface's flowmeter via the quick
connect or DISS fitting you
has been determined and regulations require that waste anesthetic gases must be
collected and removed from the premises for health reasons, thus the existence
of this device.
systems can be classified into two major categories, passive and active
systems. A passive system essentially is no more than a hose that directs the
flow of waste gasses to a location where it can be safely vented, generally
outside a building or into a non-recirculating ventilation system. Systems classified as active can be further
grouped into blower in a box (low vacuum) systems or central vacuum
systems. Blower-in-a-box systems are
just that, they have a blower in a box that blows the gas out of the building.
Piping is connected from each device to be "scavenged" into the box. The
negative pressure in the piping and box is in the order of magnitude of -2 mmHg.
This limits the number and length of drops, connections to machines,
which these systems can handle. As will be seen below even this low vacuum
pressure will require the use of a scavenging interface of some type. Central vacuum systems generate a much greater
negative pressures, around -450 mmHg and can accommodate many drops and long
piping runs. These systems can also be
used for surgical and tracheal suctioning.
is for the latter classification of scavenging systems, the central vacuum
system, that this interface was designed.
in practice breathing systems are generally operated in either an open or
semi-open mode they all must have some way to allow the excess fresh gas
introduced into the systems to be vented. Otherwise, the pressure within the
system, which includes the patient, would continue to increase until something
ruptured. That something would probably be the lungs of your patient. Therefore, every breathing system is equipped
with some form of automatic pressure limiting (APL)
valve also called a pop-off valve the purpose of which is to vent just enough
gas from within the system such that the pressure within does not exceed the
desired safe level. The pressure at
which an APL valve vents the gases
is generally adjustable. Actually
however APL valves are most often
set either fully "open" during spontaneous breathing of the patient or fully
closed in order to bag or mechanically ventilate the patient. Fully "open" in the case of APL valves does not mean that there is absolutely
no opening pressure or resistance to flow.
If this were the case there would effectively be a big hole in the
breathing system, its contents would be free to flow out and the breathing bag
would not hold enough volume to accommodate the patient's next breath. Thus every properly operating APL valve has some finite, albeit very low, opening
pressure. Ideally this pressure is
enough only to keep the breathing bag full and no more. Most APL
valves do not permit gas to flow through them until the pressure in the system
increases to somewhere between 0.5 and 2 cmH2O, that is then called its opening
pressure. This is not much pressure when you consider that 1 psi is equal to
about 70 cmH2O pressure, which for the discussion below is also about equal to
50 mmHg. Doing the math you can see that
1 cmH2O is equivalent to 0.014 psi., not much!
suction and or EVAC (evacuation) systems are available in many hospitals today
for other purposes such as surgical or tracheal suctioning but the same system
can also be used for handling such pollutants as are discharged from anesthesia
machines. The negative pressure in these
systems however is in the neighborhood of
-450 mmHg; this converts to about -630 cmH2O or -6 psi.
can be seen that if you were to connect a negative 630 cmH2O vacuum source up
to an APL valve with an opening
pressure of 1 cmH2O that in most cases, depending on the design of the valve,
the valve would be sucked open and it
would not take long for the gas in your breathing system, breathing bag and
patients lungs to be completely evacuated.
Some APL valves are
constructed in a manner that will cause them to get sucked closed if too great
of a negative pressure is applied to them.
This will prevent the breathing system from being drained dry but this
also prevents the excess gas from escaping therefore the pressure will continue
to rise in the system a rate proportional to the fresh gas flow rate. The problem is similar to what you have seen
when someone forgets to open the pop-off valve after bagging the patient a
couple of times. The breathing bag
eventually becomes over distended and the pressure within causes varying
amounts of lung damage until the problem is noticed and the pressure relieved.
In either case this is not good for the patient, and there in lies the need for
this vacuum/scavenging interface. This is a device that couples two
incompatible systems so that they will work with each other.
properly functioning scavenger interface, as we see above, should allow for the
removal of all gases that exit an APL
valve without interfering with its delicate operation. The scavenging system
cannot apply any negative pressure to the device it is scavenging greater than
the opening pressure of that device's APL
scavenging interfaces provide a needle valve to regulate the amount of suction
that is applied to the system but no other interface quantify the amount of
scavenging flow nor do any permit fine enough adjustment to make this an easy
Hallowell EMC Vacuum/Scavenging
Interface has been designed in such a way that even at high scavenging flows
the negative pressure applied to the devices being scavenged never comes close
to their opening pressures. See the
graph on the next page.
Replaceable Parts List:
Part # Description
tapered for 19mm tube
Scavenger flow 1-10 lpm
2 Liter EVAC Purple Reservoir
DOCA3136 Operating Manual, Vac/Scav Interface
the vacuum system running and connected adjust the flowmeter to obtain the
desired scavenging flow rate. If you are
not sure what flow rate you should be using start with 5 lpm.
idea is to have the scavenging flow as low as possible so as not to over tax
the vacuum system, but high enough to keep up with the average discharge from
the devices you are scavenging. The
reservoir bag exists to accommodate short periods of high discharge such as
when you empty the breathing bag or press the flush button (something I highly
recommend avoiding with any "small animal" patient connected).
during low or moderate flow anesthesia the fresh gas flow rate is set at 2 lpm
or much lower. The patient will uptake a
portion of that flow and the balance is "popped off" to the scavenger. If you run your anesthesia system with 2 lpm
fresh gas flow a scavenging flow of 5 lpm would end up drawing about 3 lpm of
room air as well as the average waste gas discharged from the APL valve.
you are using higher fresh gas flow rates or are frequently emptying the
breathing bag and flushing or adjusting the O2 flowmeter to compensate you may
need to set the scavenging flow rate higher.
With lower flows it could certainly be set lower.
appropriate the scavenging flow setting is for the way you operate your
anesthesia system can easily be judged by observing the size of the reservoir
bag frequently through a few cases.
Decrease the flow rate till you see that over the long run the bag never
seems to empty completely. Then increase
the flow by 50% for a comfortable margin.
After you have done this you will find that you will not have to change
the setting again given that you continue to operate your anesthesia system in
the same manner and that your vacuum level remains the same.
interface is made of solid brass and is chrome plated for durability and easy
cleaning. Simply wipe it clean with a
damp cloth when required, Get no alcohol on the plastic flowmeter.
charcoal canister serves a dual purpose in this system. The system will not
function properly without the charcoal canister. Primarily it provides the slight pressure
drop required for trouble free scavenging and filters dust and hair from
incoming room air. Far less frequently, when made necessary by a suction system
failure or disconnect, flow is revered through the canister and it absorbs the
volatile anesthetics (not N2O) from the waste gases as they are discharged into
the room preventing eventual over distention of the patients lungs. The interface can also be used in this latter
"back up" mode during transport or for cases where vacuum is unavailable.
amount of dust accumulation at the bottom of the canister and its
reserve capacity to absorb more anesthetic must be checked periodically
to insure proper performance of the system.
the canister periodically and comparing it to what the canister weighed when it
was placed in service (See the Receiving section above) best estimates this
reserve capacity. The frequency with
which you check the canisters weight depends on your usage but should be done
soon after any known suction system failure or disconnect or any transport
cases. Be sure to clean off as much dust
accumulation as possible from the underside of the filter before weighing it.
Before the canister gains 50 grams over the weight recorded when it was put
into service (its point of exhaustion) it should be discarded and replaced as
recommended by the manufacturer. It is
advisable to get into the habit of using the same gram scale to weigh the
canisters. Exhausted canisters are to be
disposed of as ordinary trash.
As always your comments and
feedback on our products are always appreciated.
I can be contacted at 413-445-4263 or
Hallowell EMC Model 2000 Veterinary
with bellows attachments accommodating patients
from 2 to 400 lbs. Maintain normocapnia
reducing the risks associated respiratory acidosis and decreased blood pH
levels leading to cardiac complications. This is especially important to your
obese patients or those undergoing perineal, perianal or PU surgeries due to
their positioning. Smooth out rocky anesthesias, free a pair of hands when you
really need them.
Hallowell EMC Anesthesia
WorkStation (AWS). This new concept
is a complete anesthesia machine (less the vaporizer of your choice) for
animals from 150 grams to 6 or 7 kg. It
is the same size as the model 2000 but incorporates a heated circle rebreathing
system for the patients you previously had to put on a non-rebreathing
system. Also incorporated is an integral
volume ventilator. Should you want to
mechanically ventilate the patient just switch the control from STANDBY to
VENTILATE. Now available is a 200ml
attachment effectively doubling the maximum deliverable tidal volume (TV) and
size of the patient it will accommodate.
Hallowell EMC Heated Hard Pads,
literally bullet proof (.22 caliber), are a welcome relief from the so frequent
hassles of patching or replacing the flexible heating pads. These solid polycarbonate pads will attach to
any existing hot water circulating pump you may have with the provided
connectors and still permit you to use your old flexible pads when desired.
Hallowell EMC lightweight equine
wyes and breathing system tubes. The
wyes are light plastic, will accommodate both Drager and Bivona style metal
endotracheal tube connectors as well as the Bivona and Cook funnel fit
connectors. They are available with gas
sampling ports that draw from within the ET tube. We also have an equine bronchial-blocker
tube for lung separation applications.
The breathing system tubes are also light, clear and easy to clean and
Name: ____________________________ Date: _____________
Self-assessment review quiz:
- What are the general
classifications of scavenging systems?
- Why is scavenging
- What does APL stand for?
- What conditions could
cause the breathing system bag to be drained by a scavenging system, i.e.
what pressures would need to be in what relationship to each other?
- What should a properly
operating scavenging system provide for?
- What observations could
you make that would indicate to you that the scavenging flow is
inappropriately set? What would you
do to correct it?
- That was easy, what else?
- What two things should be periodically checked
to insure continued proper functioning of this interface? When or how often? How is this done?